Biotribology of Diarthrodial Joints

关节生物摩擦学

• 批准号: 7088785
• 负责人: GERARD A. ATESHIAN
• 金额: $ 26.88万
• 依托单位: COLUMBIA UNIV NEW YORK MORNINGSIDE
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-06-15 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7088785
• 关键词: animal tissue; articular cartilage; atomic force microscopy; biomechanics; confocal scanning microscopy; fluorescence microscopy; gamma globulin; hyaluronate; joints; mechanical pressure; mechanical stress; phospholipids; protein degradation; serum albumin; surface property; synovial fluid

DESCRIPTION (provided by applicant): The primary function of articular cartilage is to serve as a bearing material for diarthrodial joints. As part of our recent studies, we have demonstrated from theory and experiments that cartilage can provide efficient lubrication even under boundary friction, primarily because its interstitial water may pressurize considerably under loading. In this application, we propose to follow-up on these findings by addressing specific questions related to the functional effectiveness of the lubrication mechanism in diarthrodial joints: a) Since the friction coefficient is observed to increase over time to functionally detrimental values under laboratory testing conditions, what makes it stay sufficiently low under physiological loading conditions in situ? b) How effective are the boundary lubricants in synovial fluid, after accounting for the role of interstitial fluid load support? c) Is there a functionally significant mixed lubrication regime in the initial response to joint loading during which lubricant is temporarily trapped between articular surfaces, and if so, does the duration of this mixed regime depend on the type of lubricant? While it may be attractive from the clinical and commercial perspective to consider joint lubrication in terms of a phenomenon arising from synovial fluid and its constituents (e.g., intra-articular injection of hyaluronan and other "lubricants"), their relative contribution to the low frictional properties of articular cartilage are not well understood. With an original theoretical framework, validated using novel experimental techniques developed over the past two granting periods that clearly describe how articular cartilage is able to exhibit extremely low friction coefficients even in the absence of synovial fluid, we now propose studies to determine the contribution of boundary lubricants in synovial fluid to the functional effectiveness of the lubrication mechanism in diarthrodial joints. Our proposal is timely in light of the recent resurgence of interest in proteins in synovial fluid or in the superficial zone of articular cartilage that may assist in the tribological response. To investigate our hypotheses, the proposal incorporates some novel applications of Atomic Force Microscopy (AFM), Total Internal Reflectance Fluorescence (TIRF) microscopy, and Scanning Confocal Microscopy (SCM) techniques.

描述（由申请人提供）：关节软骨的主要功能是作为关节间关节的承重材料。作为我们最近研究的一部分，我们已经从理论和实验中证明，即使在边界摩擦下，软骨也可以提供有效的润滑，主要是因为其间隙水在负载下可能会相当大地加压。在本申请中，我们建议通过解决与关节内润滑机制的功能有效性相关的具体问题来跟踪这些发现：a）由于在实验室测试条件下观察到摩擦系数随时间增加至功能有害值，是什么使其在原位生理负荷条件下保持足够低？B）考虑到间质液负荷支持的作用后，滑液中边界润滑剂的有效性如何？c）在关节负荷的初始反应中，是否存在功能上显著的混合润滑状态，在此期间，润滑剂暂时被困在关节面之间，如果是，这种混合状态的持续时间是否取决于润滑剂的类型？虽然从临床和商业角度考虑关节润滑在由滑液及其成分引起的现象方面可能是有吸引力的（例如，关节内注射透明质酸和其它“润滑剂”），但它们对关节软骨的低摩擦性质的相对贡献还没有被很好地理解。与原始的理论框架，验证使用新的实验技术开发在过去的两个授予期间，清楚地描述了关节软骨是如何能够表现出极低的摩擦系数，即使在没有滑液，我们现在提出的研究，以确定边界润滑剂的贡献滑液的润滑机制在diarthodial关节的功能有效性。我们的建议是及时的，在滑液或关节软骨的浅表区，可能有助于摩擦学反应的蛋白质的兴趣最近复苏。为了研究我们的假设，该提案结合了原子力显微镜（AFM），全内反射荧光（TIRF）显微镜，扫描共聚焦显微镜（SCM）技术的一些新的应用。